This invention relates generally to the field of food serving dishes or bowls typically used for buffet type serving by restaurant and similar facilities, and snore particularly to an improved form of chafing device adapted to preserve the contents at a predetermined heated temperature over a substantial period of time.
It is known in the art to provide chafing dish devices having a base element adapted to be supported by a serving table along with similar devices containing other items of food. Means in the form of replaceable trays are selectively engaged upon the base element with a fresh supply of a particular food as the contents of an installed tray are removed. The base element includes a movably supported cover usually pivotally engaged along an edge thereof which is manually opened by a user to permit access to the contents of the tray, following which the cover is manually closed. In some cases, the cover is counterbalanced to remain in relatively open condition. In the case of relatively larger base elements there is provided heating means, typically using solid alcohol fuel to replace heat lost from the food during the period in which the cover is opened.
Such devices have been known in the art for many years. The principal problem from the standpoint of a user is that he or she, prior to opening the cover, is already carrying at least one plate or dish, and must perform the operation of opening the cover, transferring a desired portion of food, and closing the cover with another hand, as well as replacing a serving implement while maintaining the plate or plates in horizonal orientation. As a result, the user, particularly if elderly, often chooses or neglects to close the cover which remains in opened condition until the arrival of the next user, with undesirable heat loss in the remaining contents of the tray.
Briefly stated, the invention contemplates the provision of an improved chafing dish construction which addresses the above-described problem. To this end, the described embodiment provides for the sensing of the presence of a user proximate to the table area supporting the chafing dish, and using this information to initialize the operation of mechanical means for opening the cover, and maintaining the same in open condition until the user has moved away from the sensed location, at which point the means serves to close the cover pending the arrival of a subsequent user or service personnel. A time delay is provided to function where the subsequent user arrives within a relatively short time increment. The cover element is of arcuate configuration and is mounted for pivotal movement about its axis, motivated by a battery powered motor which drives a side mounted cog belt which is entrained on a corresponding cog pulley on the axis of rotation of the cover. The belt carries cams which operate electrical switches controlling operation of the motor. The motor and its rechargeable batteries are preferably mounted within an insulated enclosure to dampen operational noise and are connected to the cog belt through a flexible-coupling. The presence of a user is sensed by known passive infra-red sensing means located at the front of the device and in a position so as not to be affected by heating means disposed beneath the replaceable tray which supports the food, Means is also provided for disconnecting the motor in the event that a user attempts to close the cover during a period of time delay. During normal use, the cover element will be pivoted through approximately a ninety degree or one-hundred eighty degree arc with the principal axis of rotation disposed parallel to the principal axis of the food tray.